Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Color Vision”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,081 records · Page 60Linked to original sources
PubMed1993

Red-green color discrimination in peripheral vision.

Color discrimination thresholds were measured for four colors from the red-green portion of the visible spectrum. Thresholds were measured for a stimulus field 1.5 deg in diameter in the fovea and at three locations on the nasal retina (eccentricities of 5, 20 and 40 deg). Outside the fovea threshold increased exponentially with eccentricity and the slope of the function was similar for all four standard colors. Peripheral thresholds were adequately described by an equation developed for foveal red-green thresholds by Boynton and Kambe [(1980) Color Research and Applications, 5, 13-23] and also by a modified form of this equation containing a rod term. Differences between foveal and peripheral thresholds were characterized by changes in two coefficients in the equations. The CIELUV color difference equation also provided a reasonably good description of peripheral thresholds.

Adult↗
PubMed1999

Shape Perception in the Honeybee: Symmetry as a Global Framework.

This study is concerned with the honeybee's spatial vision in light of the spatial signals that natural flowers display. A large amount of behavioral data shows that bees are perfectly adept at learning and exploiting a variety of spatial cues in the task of recognizing and discriminating between visual stimuli. These cues include spatial frequency, distribution of contrasting areas, orientation of contours, size and distance, different types of edges, and symmetry (or, in a broader sense, geometry). Symmetry constitutes a global feature that is only one of the cues that the target offers. Symmetrical stimuli always contain several further spatial cues that become relevant as the bee comes nearer to the stimuli. The results reviewed here show that the spatial signals used by the bee depend on whether the stimuli are presented on a horizontal or a vertical plane, on whether bees make their choices at a lesser or a greater distance, and on whether the target's image is stationary at the level of the eye, as opposed to moving. Further, it is shown that pattern recognition in the bee does not always require a learning process (i.e., several types of response to visual stimuli are based on hard-wired, innate behavioral programs). Finally, the results show that although it is not a prerequisite for spatial vision, color vision participates in spatial vision, whereas spatial cues extracted from image motion are processed by a color-blind system.

Journal Article↗
PubMed2001

Minimum color differences for discriminating mismatch between composite and tooth color.

PURPOSE: The purpose of this study was to determine if there are differences between patients and dental professionals in their ability to identify small color differences (deltaE) in composite resin restorative materials in vitro and to determine the deltaE that would indicate acceptability of color match between a restoration and an adjacent tooth. MATERIALS AND METHODS: Subjects were asked to evaluate composite resin disks to distinguish acceptability of deltaE between disk pairs. Color difference discrimination of dental professionals groups D1 (dentists, n = 12) and D2 (dental auxiliaries, n = 12) was compared to that of dental patient groups P1 (patients, n = 12) and P2 (scientists, n = 12). Each group was pretested for normal color vision. Color differences between a standard and restoration disks of composite were measured in Colour Measurement Committee (CMC) (1:1) color units. Data were analyzed by logistic regression, and results were used to calculate a probability level for minimal acceptance or rejection of AE for all observers. Mean 50:50 deltaE replacement points (RP) for each group were obtained and analyzed by analysis of variance, and the Tukey pairwise comparison test was applied (alpha = 0.05 for all statistical analyses). RESULTS: There were significant differences found between the experimental groups (p = .020). Group D2 (mean 50:50 deltaE RP = 1.78) proved to be more discriminating in accepting differences between tooth and composite resin restorative material color than group P1 (mean 50:50 deltaE RP = 2.69). The mean 50:50 deltaE RP for all subjects was 2.29 CMC (1:1) units. CLINICAL SIGNIFICANCE: The ability to generate an excellent color match between a tooth-colored restoration and the tooth is critical to esthetic success. This study demonstrates that patients are not as discriminating in their ability to identify small color differences between composite restorations and the tooth as are dental professionals. Dental auxiliaries proved to be more discriminating in accepting differences between tooth and composite resin restorative material color than were patients.

Analysis of Variance↗
PubMed2005

Long-term visual pathology in children with significant perinatal complications.

Eye research in infants who experience significant perinatal complications has been restricted to evaluation of structural ocular disease and spatial vision, and results show that these aspects of vision are at increased risk for abnormal or delayed development. To expand upon previous work, a battery of 17 vision tests was employed to assess, comprehensively, long-term outcome of functional vision. Seventy-six children (38 males, 38 females), between the corrected ages of 2 years 11 months and 10 years 2 months (mean 6y 6mo) with various significant complications (e.g. very preterm birth, bronchopulmonary dysplasia, intraventricular hemorrhage) were compared to normally developing, age-matched control children (n = 61; mean age 7y 1mo) on measures of visual acuity, contrast sensitivity, stereoacuity, peripheral vision, color vision, astigmatism, and binocular alignment. Results showed that at-risk children had more test results that fell within the suspect or abnormal range. At-risk children also had a slightly higher incidence of ocular disorders (e.g. strabismus) and refractive error. These data imply that children who experienced significant perinatal risk factors are at risk for long-term deficits of functional vision. However, most of these deficits appear to be relatively mild.

Bronchopulmonary Dysplasia↗
PubMed2005

[Influence of cataract and intraocular lens surgery on health-related quality of life].

PURPOSE: To evaluate the vision-related quality of life(QOL) in patients undergoing cataract surgery with the Japanese version of the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25). SUBJECTS AND METHODS: Subjects were 110 patients [70.4 +/- 9.2 (mean +/- standard deviation) years old] undergoing bilateral cataract surgery. Best-corrected visual acuity was 20/30 or worse in both eyes. The VFQ-25 was recorded before and 2 months after phacoemulsification and foldable intraocular lens implantation, and the influence of various clinical parameters was assessed. The VFQ-25 was also recorded in 69 glaucoma patients with visual field defects in both eyes, and in 31 normal subjects. RESULTS: The VFQ-25 scores before cataract surgery were as low as the scores obtained in glaucoma patients. Cataract surgery significantly improved VFQ-25 scores to the level of normal subjects Statistically significant improvements were observed in subscales such as general vision, near activities, distance activities, driving, peripheral vision, color vision, social functioning, dependency, role difficulties, mental health, and total score (p<0.001, paired t-test). The degree of improvement in VFQ-25 scores did not correlate with preoperative or postoperative visual acuity, uncorrected or corrected. The VFQ-25 scores improved more in younger patients, and improvement in the general vision subscale showed a significant negative correlation with age (r= -0.286, p=0.009, Pearson correlation coefficient). The degree of posterior subcapsular cataract in better eyes showed significant correlation with the improvement in subscales, such as distance activity (r =0.413, p<0.001), driving (r= 0.449, p=0.015), social functioning (r=0.308, p= 0.004), mental health (r=0.330, p=0.002), dependency (r=0.323, p=0.003), and total score (r=0.328, p=0.002). Other types of cataract had no correlation. Men tended to show more improvement in VFQ-25 scores by surgery than women, except for the dependency subscale. CONCLUSION: The current study quantitatively demonstrated that vision-related QOL is significantly impaired in patients with cataract, and that cataract surgery dramatically improves patients' QOL.

Adult↗
PubMed1990

Clinical features of occipital infarction.

Occipital infarction may only cause visual symptoms. A homonymous visual field defect of various configurations is the most common clinical finding. Additionally, central vision, color vision and visual associative function also may be impaired. In this paper three cases of occipital infarction are presented and the clinical features of this condition discussed.

Aged↗
PubMedDate not supplied

[Status of the visual system in operators causing railway accidents].

One hundred and eighty four engine-drivers aged 21-60 years were examined; 91 from them provoked an accident not stopping the train in front of the "Stop" signal; 93 constituted a control group. Compared was the status of the visual system and the efficiency of the visual functions such as: binocular vision, color vision and asthenopia, mesopic vision and the sensitivity to glare. In engine-drivers of the "accident-prone" group one observed an increased sensitivity for glare. The authors suggest it would be necessary to introduce to the qualification examinations for engine-drivers the evaluation of the sensitivity to glare and of the visual ability in mesopic conditions.

Accidents, Occupational↗
PubMed1993

[Glaucoma as a cause of blindness].

The problem of glaucoma as a cause of blindness is discussed. WHO has proposed five classes of sightlessness on the sole basis of visual acuity without taking into account sense of luminosity, peripheral vision, color vision. In addition, different nations have different tables for evaluating the severity of the handicap so that data on this subject cannot be compared. This is why the problem of blindness due to glaucoma is very complicated and the concept of blindness has to be standardized as well as the method of epidemiologic research. The investigation starts from a list of the most reliable sources: records of associations of sightless subjects, lists of sightless persons receiving an invalidity pension, filed research, records of support activities and transversal population studies. This is followed by a general review of causes of blindness worldwide, their prevalence according to age and sex, and especially the causes of blindness in various nations and in different regions of Italy. Last, the percentage of loss of eye-sight due to glaucoma is examined.

Africa↗
PubMed1997

Blue-yellow deficiency in workers exposed to low concentrations of organic solvents.

OBJECTIVES: To evaluate the effects of low concentrations of organic solvents on color vision. METHODS: Color vision was examined in 24 workers exposed to mixtures of solvents and in 24 control subjects. Exposure to mixtures was below the threshold-limit values. Color vision ability was assessed using the Ishihara plates (to screen for congenital dyschromatopsia), the Farnsworth panel D-15 test, the Lanthony desaturated panel D-15 test, and the Standard Pseudoisochromatic Plates part 2 (SPP2 test). RESULTS: The comparatively less sensitive Farnsworth panel D-15 test failed to show any difference between the groups, but the Lanthony panel D-15 desaturated test as well as the SPP2 test showed a significant impairment in the exposed group. Errors were of the blue-yellow type. CONCLUSION: This study gives further evidence that even mixtures of organic solvents at concentrations below the threshold-limit values may impair color vision.

Adult↗
PubMed1989

Using argon laser blue light reduces ophthalmologists' color contrast sensitivity. Argon blue and surgeons' vision.

Color contrast sensitivity was measured in laser operators before and after laser use. After argon blue-green laser treatment sessions, sensitivity was reduced for colors lying along a tritan color-confusion line for several hours. This acute effect is due to specular "flash-backs" from the aiming beam off the surface of the contact lens. It is caused only by argon 488-nm light, when the aiming beam intensity is high. In addition, a correlation has been demonstrated between the number of years of laser experience and a chronic reduction in tritan color contrast sensitivity. It is suggested that repeated acute changes caused by the argon lasers may cause cumulative effects and produce a chronic threshold elevation. A simple method of eliminating the acute effect is documented.

Adult↗
PubMed1988

Ocular effects and safety of antimalarial agents.

The clinical experiences with 1,500 patients receiving chloroquine or hydroxychloroquine over a 15-year period are reviewed. Forty-six patients with confirmed irreversible, bilateral, early chloroquine retinopathy have been followed prospectively since 1980. Patients presenting with normal color vision and relative paracentral scotomas appear not to progress over short-term follow-up of five years. Retinopathy in patients presenting with less than 20/20 vision, abnormal color vision, and positive fluorescein angiography may progress even if treatment with the medication is discontinued. The Amsler grid is an effective method of screening patients taking antimalarial agents for early relative paracentral scotomas. Color vision testing and fluorescein angiography are useful in elderly patients with age-related macular disease when visual field testing is unreliable.

Antimalarials↗
PubMed2003

Successful shade matching--what does it take?

Dental practitioners can avoid expensive and embarrassing shade matching errors by learning about the structure and function of the eye and how to control the external and internal factors that affect human vision. The color of objects is identified by the visible light that they reflect; objects can reflect only the light that shines upon them. Eyes sense the hue, intensity, and saturation of light, so lighting of proper intensity and color balance is necessary for consistent, correct shade-matching. Although sunlight is the most common standard for good lighting, in everyday practice, it cannot be used for shade matching because of its extreme variability with weather conditions, time of day, and season of the year. In addition to external factors such as lighting, conditions internal to the observer also play a role in accurate color perception. Color vision confusion (CVC), often called "color blindness," is a serious handicap for dental professionals. The popular assumption is that very few people are afflicted; in fact, all people suffer from some level of color vision confusion. This distortion of visual information can be permanent or transitory. Therefore, controlling these variables can lead to color matching success.

Color Perception↗
PubMed1990

Visual search for color differences with foveal and peripheral vision.

Color differences required for fast parallel searches were measured for small and large display fields. The main purpose of the measurement was to test the hypothesis that serial searches obtained with small color differences in large display fields are due to poor discrimination in the peripheral visual field and to the need for foveal fixation. Results do not support this hypothesis but show that the color differences required for parallel search are just as large in a display confined to an area roughly the size of the fovea as in a large display. However, results also show that the color difference required for a fast, parallel search is dependent on the size of the stimuli in a large display field. This result is consistent with the possibility that poor discrimination in the periphery may contribute to the size of the required differences if the stimuli are small.

Color Perception↗
PubMed2000

Assessment of fresh pork color with color machine vision.

Currently, fresh pork color is visually evaluated using either the Japanese Pork Color Standards (JPCS) or the National Pork Producers Council Pork Quality Standards (NPPC) as a reference. Although useful, visual evaluation of meat color can vary with evaluator and may be quite expensive. In this study, three separate studies were used to compare the ability of color machine vision (CMV) and untrained panelists to evaluate pork color. Panels visually evaluated over 200 pork loin chops using either the JPCS or NPPC reference standards. Results from each panel were used to evaluate the ability of the CMV to sort pork loin chops based on the same criteria. Representative samples, typical of each color class, were used to train neural-network-based image processing software. After training, the CMV system was used to evaluate quality classes of pork samples based on color distribution. Classification by CMV was compared with the average panel score, rounded to the nearest integer. Training the CMV system using images of actual meat samples resulted in a stronger correlation to panel scores than training with either set of artificial color standards. Agreement between the CMV system and the panels was as high as 90%. Agreement between individual panelists and the integer panel average (52 to 85%) was less than that observed for CMV classification. Finally, the on-line performance of CMV using a laboratory conveyor system was simulated by repeatedly classifying 37 samples at a speed of 1 sample per second. Collectively, these results demonstrate that CMV is a rapid and repeatable means of evaluating pork color.

Animals↗